The subject invention relates to improvements in video processing systems. The subject invention finds particular application in a slow scan digital video processor utilizing microprocessor techniques.
Prior art video signal processing systems for converting a video signal to digital format and storing frames of digital data are known. See U.S. Pat. No. 4,148,070. Such video processors have typically used analog or a combination of analog and digital techniques to detect and regenerate sync signals required by the video format. It has appeared desirable to the inventors to devise a technique whereby the sync detection functions can be accomplished in a microprocessor environment, avoiding as many analog functions as possible. Among the obstacles to implementing such a technique is the necessity to properly synchronize microprocessor operation to the incoming video signal. Without such synchronization improper storage of the video data will result.